Designers developing piloted flying vehicles capable of taking off and landing on standard landing strips are always confronted with a great challenge. To achieve minimum speeds for taking off or landing, the wing of a flying vehicle is to have a relatively large surface area. A wing of a large surface area, however, always has a high drag coefficient (Cx) that interferes substantially with flight at high speeds. Small surface areas of the wings in the nose and tail parts of an aircraft are enough for flight at cruising speeds. This principle is used, for example, in the U.S. GAM-63 RASCAL tactical cruise missile that can fly at speeds over 3,000 km/hr.
The air forces have long been flying aircraft having variable-geometry wings, for example, the U.S. F-14, Russian SU-22, SU-24, and so on. This design allows an aircraft to take off and land at relatively low speeds, and flight at high speed is made more economical by reducing the Cx of the wing by varying its geometry. Typically, the wing of a modern aircraft has slats, flaps, ailerons, and fuel tanks. These components give a variable geometry wing a very complex design. Its elements have a large size and weight, and are unreliable, complicated, and expensive to make and maintain. For these reasons, a variable-geometry wing is not used in civil aviation.
A prior art aircraft has a pair of wings joined to the fuselage by hinged fitting units and can be turned relative to the axes of the fitting units for movement to the takeoff and landing position during takeoff and landing or to the retracted position in cruising flight or when parked (U.S. Pat. No. 5,984,231 of Nov. 16, 1999).
A drawback of a wing of this aircraft design is that each wing has a single fitting unit that is subjected to high aerodynamic loads as the wing is turned in flight.
Another drawback of this wing design is that the wing configuration continues to develop Cx and fuel requirements of the aircraft are reduced insignificantly.